Respiratory viral infections, particularly by human rhinoviruses (HRV), play important roles in inception and exacerbation of asthma. The goal of this PPG is to identify the HRV and host genetic determinants underlying the development of asthma in children and to determine the mechanisms by which HRV infections contribute to asthma pathogenesis. The Virology Core is established to provide this PPG with the capability to identify all common respiratory viruses and the individual serotype/strain of HRV associated with childhood asthma and to quantify the amount of HRV in the airways of subjects with wheezing. This Core will first examine comprehensively all nasal specimens with a new high-throughput, multi-target, sensitive and accurate viral assay called Respiratory MultiCode Assay that is capable of simultaneously detecting hundreds of strains of all common respiratory viruses belonging to 8 distinct groups (HRV, RSV, parainfluenza, influenza, metapneumovirus, enterovirus, coronavirus, and adenovirus) with a >4 hour completion time for a 96- well plate of samples. When a HRV is detected, its serotype/strain will be determined by a new molecular genetic typing method and HRV viral load in airway fluids will be measured with a new pan- HRV quantitative (q) PCR assay. In addition, this core will (1) provide uniform HRV stocks (including purified viruses, radiolabeled viruses, viruses with inactivated genome and high liter inoculum of 101 HRV serotypes), cDNA clones of selected serotypes and related materials and (2) perform standardized infectivity, qPCR assay and attachment assays of HRV in support of Projects l-lll, and (3) provide cultures of human bronchial epithelial cells for use in Projects II and III.